This probably applies to other weapons as well, but it was with Falcon Swords that I noticed it.

I recently found a Falcon Sword, I see in the ladder many classes using them.
When I checked s_info it only lists Duelists, Wild-Talents, and Rune Knights as having skill in the Falcon. No other class even has a Zero skill.
Are the other classes just using it Unskilled and ignoring penalties?
Or, is something else going on?

Falcon swords have good damage dice and are light, so they are good for everyone except Maulers
I didn't know about the skill thing, but my impression is that skill penalties are not the end of the world, and would be outweighed in this case at least by the excellent damage
I haven't checked the skill thing, it is bad if a weapon proficiency is capped at unskilled, but if it merely starts at unskilled and can improve then that is not a problem